I bet that you have never seen this pen and I am not surprised. I've seen and bought it only once and I'm totally not regretting it.
Patio is a Polish brand (the site is in Polish), but I haven't found this pen in their catalog. Upon closer examination, you can see that many of their products look a great deal like world-famous pens (Pilot G2, Pilot Frixion, Stabilo Bionic Worker). Looks like this is not the case. Or can you remember some similar looking pen?
Maybe it's some older stock (ex. from year 2013 or even older)? Maybe it was some kind of co-operation between Patio manufacturer and Tesco vendor? Eh, mystery, fortunately not to be solved by us.
But let's see how it writes!
It's a rollerball, so the showthrough and bleedthrough is quite significant on cheaper office paper. It doesn't bug me since I have lots of one-side prints to write on, but it would be a bit of a problem if used in cheaper notebooks or school exercise books (I came across 55 gsm exercise books here, that's pretty thin).
+ smooth writing
+ crisp, clean line
+ really black
+ easy disassembling
+ washable ink
- difficult (or impossible) to buy
- cap tends to fall off
- tends to bleedthrough and showthrough
- occasional scratchy ball
The three pens cost me 30 CZK (about 1 € or 1,2 USD) and seriously, they are worth much more. Shame I can't find them anywhere any more. It's so great pen!